When cancellous bone becomes diseased, for example, because of osteoporosis, avascular necrosis, or cancer, the surrounding cortical bone becomes more prone to compression fracture or collapse. This is at least in part because the cancellous bone no longer provides interior support for the surrounding cortical bone. The bone disease may also affect the strength and integrity of the surrounding cortical bone, further disposing the bone to fracture and/or collapse.
There are 2 million fractures each year in the United States, of which about 1.3 million are caused by osteoporosis alone. There are also other bone diseases involving infected bone, poorly healing bone, or bone fractured by severe trauma. Moreover, the use of various drugs, such as steroids, tobacco and/or the excessive intake of alcohol, can significantly degrade bone quality. Any of these conditions, if not successfully addressed, can result in fracture and/or collapse of bone, causing deformities, chronic complications, and an overall adverse impact upon the quality of life.
U.S. Pat. Nos. 4,969,888 and 5,108,404 disclose apparatus and methods for the fixation of fractures or other conditions of human and other animal bone systems, both osteoporotic and non-osteoporotic. Among other inventions, these patents disclose devices and methods that employ an expandable body to compress cancellous bone and/or create an interior cavity within the targeted bone. The cavity receives a filling material, which hardens and provides renewed interior structural support for cortical bone.
The better and more efficacious treatment of bone disease that these patents promise can be more fully realized with improved systems and methods for making and deploying expandable bodies in bone.